U.S. patent application number 16/835565 was filed with the patent office on 2020-07-16 for storage method for hydrochlorofluoroolefin, and storage container for hydrochlorofluoroolefin.
This patent application is currently assigned to AGC Inc.. The applicant listed for this patent is AGC Inc.. Invention is credited to Tamaki CHINSOGA, Masato FUKUSHIMA.
Application Number | 20200224822 16/835565 |
Document ID | / |
Family ID | 66173271 |
Filed Date | 2020-07-16 |
United States Patent
Application |
20200224822 |
Kind Code |
A1 |
CHINSOGA; Tamaki ; et
al. |
July 16, 2020 |
STORAGE METHOD FOR HYDROCHLOROFLUOROOLEFIN, AND STORAGE CONTAINER
FOR HYDROCHLOROFLUOROOLEFIN
Abstract
To provide a method for safely and stably storing a
hydrochlorofluoroolefin filled in a container for storage,
transportation, etc. A method for storing a hydrochlorofluoroolefin
in a sealed storage container, wherein the hydrochlorofluoroolefin
is stored in such a state that a gas phase and a liquid phase
coexist in the storage container, and the concentration of air in
the gas phase in the storage container at a temperature of
25.degree. C. is kept to be at most 3.0 vol %, and a method for
storing a hydrochlorofluoroolefin in a sealed storage container,
wherein the hydrochlorofluoroolefin is stored in such a state that
a gas phase and a liquid phase coexist in the storage container,
and the concentration of oxygen in the gas phase in the storage
container at a temperature of 25.degree. C. is kept to be at most
0.6 vol %.
Inventors: |
CHINSOGA; Tamaki;
(Chiyoda-ku, JP) ; FUKUSHIMA; Masato; (Chiyoda-ku,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AGC Inc. |
Chiyoda-ku |
|
JP |
|
|
Assignee: |
AGC Inc.
Chiyoda-ku
JP
|
Family ID: |
66173271 |
Appl. No.: |
16/835565 |
Filed: |
March 31, 2020 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2018/037751 |
Oct 10, 2018 |
|
|
|
16835565 |
|
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07C 21/185 20130101;
F17C 1/005 20130101; F17C 5/02 20130101; C07C 21/18 20130101; F17C
2270/01 20130101; F17C 2221/038 20130101; C07C 17/38 20130101 |
International
Class: |
F17C 1/00 20060101
F17C001/00; C07C 21/185 20060101 C07C021/185; F17C 5/02 20060101
F17C005/02 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 20, 2017 |
JP |
2017-204017 |
Claims
1. A method for storing a hydrochlorofluoroolefin in a sealed
storage container, wherein the hydrochlorofluoroolefin is stored in
such a state that a gas phase and a liquid phase coexist in the
storage container, and the concentration of air in the gas phase in
the storage container at a temperature of 25.degree. C. is kept to
be at most 3.0 vol %.
2. The method for storing a hydrochlorofluoroolefin according to
claim 1, wherein the concentration of air is kept to be at least 1
vol ppm and at most 3.0 vol %.
3. The method for storing a hydrochlorofluoroolefin according to
claim 1, wherein the hydrochlorofluoroolefin is a C.sub.2-5
hydrochlorofluoroolefin.
4. The method for storing a hydrochlorofluoroolefin according to
claim 1, wherein the hydrochlorofluoroolefin contains
1-chloro-2,3,3,3-tetrafluoropropene.
5. The method for storing a hydrochlorofluoroolefin according to
claim 1, wherein air in an unfilled storage container is removed,
then, a liquid-state hydrochlorofluoroolefin is filled and sealed,
and the hydrochlorofluoroolefin is stored in the sealed storage
container.
6. A storage container for a hydrochlorofluoroolefin, which is a
sealed storage container in which the hydrochlorofluoroolefin is
filled in such a state that a gas phase and a liquid phase coexist,
and in which the concentration of air in the gas phase at a
temperature of 25.degree. C. is at most 3.0 vol %.
7. The storage container for a hydrochlorofluoroolefin according to
claim 6, wherein the concentration of air is at least 1 vol ppm and
at most 3.0 vol %.
8. The storage container for a hydrochlorofluoroolefin according to
claim 6, wherein the hydrochlorofluoroolefin is a C.sub.2-5
hydrochlorofluoroolefin.
9. The storage container for a hydrochlorofluoroolefin according to
claim 6, wherein the hydrochlorofluoroolefin contains
1-chloro-2,3,3,3-tetrafluoropropene.
10. A method for storing a hydrochlorofluoroolefin in a sealed
storage container, wherein the hydrochlorofluoroolefin is stored in
such a state that a gas phase and a liquid phase coexist in the
storage container, and the concentration of oxygen in the gas phase
in the storage container at a temperature of 25.degree. C. is kept
to be at most 0.6 vol %.
11. The method for storing a hydrochlorofluoroolefin according to
claim 10, wherein the concentration of oxygen is kept to be at
least 0.2 vol ppm and at most 0.6 vol %.
12. The method for storing a hydrochlorofluoroolefin according to
claim 10, wherein the hydrochlorofluoroolefin is a C.sub.2-5
hydrochlorofluoroolefin.
13. The method for storing a hydrochlorofluoroolefin according to
claim 10, wherein the hydrochlorofluoroolefin contains
1-chloro-2,3,3,3-tetrafluoropropene.
14. The method for storing a hydrochlorofluoroolefin according to
claim 10, wherein air in an unfilled storage container is removed,
then, a liquid-state hydrochlorofluoroolefin is filled and sealed,
and the hydrochlorofluoroolefin is stored in the sealed storage
container.
15. A storage container for a hydrochlorofluoroolefin, which is a
sealed storage container in which the hydrochlorofluoroolefin is
filled in such a state that a gas phase and a liquid phase coexist,
and in which the concentration of oxygen in the gas phase at a
temperature of 25.degree. C. is at most 0.6 vol %.
16. The storage container for a hydrochlorofluoroolefin according
to claim 15, wherein the concentration of oxygen is at least 0.2
vol ppm and at most 0.6 vol %.
17. The storage container for a hydrochlorofluoroolefin according
to claim 15, wherein the hydrochlorofluoroolefin is a C.sub.2-5
hydrochlorofluoroolefin.
18. The storage container for a hydrochlorofluoroolefin according
to claim 15, wherein the hydrochlorofluoroolefin contains
1-chloro-2,3,3,3-tetrafluoropropene.
Description
[0001] This application is a continuation of PCT Application No.
PCT/JP2018/037751, filed on Oct. 10, 2018, which is based upon and
claims the benefit of priority from Japanese Patent Application No.
2017-204017 filed on Oct. 20, 2017. The contents of those
applications are incorporated herein by reference in their
entireties.
TECHNICAL FIELD
[0002] The present invention relates to a storage method and a
storage container for a hydrochlorofluoroolefin, particularly a
method for stably storing a hydrochlorofluoroolefin for storage,
transportation, etc., and a container in which a
hydrochlorofluoroolefin is stably stored.
BACKGROUND ART
[0003] In recent years, a hydrochlorofluoroolefin is expected as a
new refrigerant, solvent, detergent, etc. which replaces
chlorofluorocarbons, hydrochlorofluorocarbons and
hydrofluorocarbons being greenhouse gases that destroy the ozone
layer.
[0004] Such a hydrochlorofluoroolefin is stored or transported as
filled in a sealed container under pressure at a temperature of at
most room temperature, or as liquified and filled in a sealed
container under pressure with cooling. The hydrochlorofluoroolefin
thus filled in a sealed container is in a gas-liquid state having a
gas phase and a liquid phase. And, the hydrochlorofluoroolefin in a
gas-liquid state is desired to be stored stably without causing
decomposition, oxidation or the like, in order to maintain the
quality so as to be adapted to a refrigerant, a solvent, a
detergent, etc., or to prevent deposition of impurities (solids) in
the container.
[0005] A hydrofluoroolefin having an unsaturated double bond, like
the hydrochlorofluoroolefin, is known to undergo a polymerization
reaction if oxygen is present, since oxygen becomes a radical
source. Accordingly, when a hydrofluoroolefin is stored, the
acceptable oxygen content is determined by evaluating to what
extent the hydrofluoroolefin is stable against self-polymerization
in the presence of oxygen, and further considering the economical
efficiency, e.g. the production cost (for example, Patent Document
1).
[0006] Further, with respect to use of the hydrochlorofluoroolefin,
for example, as a refrigerant, a method has been known to stabilize
the entire cooling system by assuming the presence of a refrigerant
oil, and e.g. by adding a stabilizer to stabilize a refrigerant
composition (for example, Patent Document 2). However, since the
conditions are different from stabilization of the
hydrochlorofluoroolefin in a container for storage or
transportation, and therefore, it is difficult to apply such a
method to storage of the hydrochlorofluoroolefin in a container.
Further, in the method of adding a stabilizer, it is required to
remove the stabilizer in application to a refrigerant, etc.,
whereby not only the load of the process is large, but also there
may be a case where the stabilizer cannot be completely removed by
a physical purification method such as distillation, such being
undesirable from the viewpoint of quality control.
[0007] As described above, for a hydrochlorofluoroolefin, a
technique regarding a storage method to maintain the quality to be
adapted to various applications and for safe and stable storage and
transportation, has not been established yet.
PRIOR ART DOCUMENTS
Patent Documents
[0008] Patent Document 1: WO2013/161724
[0009] Patent Document 2: WO2012/157763
DISCLOSURE OF INVENTION
Technical Problem
[0010] Under these circumstances, it is an object of the present
invention to provide a method for safely and stably storing a
hydrochlorofluoroolefin filled in a container for storage or
transportation, and a container in which a hydrochlorofluoroolefin
is stably stored.
Solution to Problem
[0011] The present invention provides a method for storing a
hydrochlorofluoroolefin and a storage container for a
hydrochlorofluoroolefin, having the following constitutions.
[0012] [1] A method for storing a hydrochlorofluoroolefin in a
sealed storage container, wherein the hydrochlorofluoroolefin is
stored in such a state that a gas phase and a liquid phase coexist
in the storage container, and the concentration of air in the gas
phase in the storage container at a temperature of 25.degree. C. is
kept to be at most 3.0 vol %.
[0013] [2] The method for storing a hydrochlorofluoroolefin
according to [1], wherein the concentration of air is kept to be at
least 1 vol ppm and at most 3.0 vol %.
[0014] [3] The method for storing a hydrochlorofluoroolefin
according to [1] or [2], wherein the hydrochlorofluoroolefin is a
C.sub.2-5 hydrochlorofluoroolefin.
[0015] [4] The method for storing a hydrochlorofluoroolefin
according to any one of [1] to [3], wherein the
hydrochlorofluoroolefin contains
1-chloro-2,3,3,3-tetrafluoropropene.
[0016] [5] The method for storing a hydrochlorofluoroolefin
according to any one of [1] to [4], wherein air in an unfilled
storage container is removed, then, a liquid-state
hydrochlorofluoroolefin is filled and sealed, and the
hydrochlorofluoroolefin is stored in the sealed storage
container.
[0017] [6] A storage container for a hydrochlorofluoroolefin, which
is a sealed storage container in which the hydrochlorofluoroolefin
is filled in such a state that a gas phase and a liquid phase
coexist, and in which the concentration of air in the gas phase at
a temperature of 25.degree. C. is at most 3.0 vol %.
[0018] [7] The storage container for a hydrochlorofluoroolefin
according to [6], wherein the concentration of air is at least 1
vol ppm and at most 3.0 vol %.
[0019] [8] The storage container for a hydrochlorofluoroolefin
according to [6] or [7], wherein the hydrochlorofluoroolefin is a
C.sub.2-5 hydrochlorofluoroolefin.
[0020] [9] The storage container for a hydrochlorofluoroolefin
according to any one of [6] to [8], wherein the
hydrochlorofluoroolefin contains
1-chloro-2,3,3,3-tetrafluoropropene.
[0021] [10] A method for storing a hydrochlorofluoroolefin in a
sealed storage container, wherein the hydrochlorofluoroolefin is
stored in such a state that a gas phase and a liquid phase coexist
in the storage container, and the concentration of oxygen in the
gas phase in the storage container at a temperature of 25.degree.
C. is kept to be at most 0.6 vol %.
[0022] [11] The method for storing a hydrochlorofluoroolefin
according to [10], wherein the concentration of oxygen is kept to
be at least 0.2 vol ppm and at most 0.6 vol %.
[0023] [12] The method for storing a hydrochlorofluoroolefin
according to [10] or [11], wherein the hydrochlorofluoroolefin is a
C.sub.2-5 hydrochlorofluoroolefin.
[0024] [13] The method for storing a hydrochlorofluoroolefin
according to any one of [10] to [12], wherein the
hydrochlorofluoroolefin contains
1-chloro-2,3,3,3-tetrafluoropropene.
[0025] [14] The method for storing a hydrochlorofluoroolefin
according to any one of [10] to [13], wherein air in an unfilled
storage container is removed, then, a liquid-state
hydrochlorofluoroolefin is filled and sealed, and the
hydrochlorofluoroolefin is stored in the sealed storage
container.
[0026] [15] A storage container for a hydrochlorofluoroolefin,
which is a sealed storage container in which the
hydrochlorofluoroolefin is filled in such a state that a gas phase
and a liquid phase coexist, and in which the concentration of
oxygen in the gas phase at a temperature of 25.degree. C. is at
most 0.6 vol %.
[0027] [16] The storage container for a hydrochlorofluoroolefin
according to [15], wherein the concentration of oxygen is at least
0.2 vol ppm and at most 0.6 vol %.
[0028] [17] The storage container for a hydrochlorofluoroolefin
according to [15] or [16], wherein the hydrochlorofluoroolefin is a
C.sub.2-5 hydrochlorofluoroolefin.
[0029] [18] The storage container for a hydrochlorofluoroolefin
according to any one of [15] to [17], wherein the
hydrochlorofluoroolefin contains
1-chloro-2,3,3,3-tetrafluoropropene.
Advantageous Effects of Invention
[0030] According to the method for storing a
hydrochlorofluoroolefin and the storage container for a
hydrochlorofluoroolefin of the present invention, decomposition,
oxidation or the like of a hydrochlorofluoroolefin is suppressed,
whereby it is possible to maintain the hydrochlorofluoroolefin with
high purity and high quality.
DESCRIPTION OF EMBODIMENTS
[0031] Now, the present invention will be described in detail
below.
[0032] In this specification, abbreviated names of halogenated
hydrocarbon compounds are described in brackets after the compound
names, and the abbreviated names are employed instead of the
compound names as the case requires. Further, with respect to a
compound having cis-trans isomers, (E) before the compound name or
after the abbreviated name means an E-form (trans form), and (Z)
means a Z-form (cis form). A compound or an abbreviated name not
denoted by (E) or (Z) means an E-form, a Z-form and a mixture of an
E-form and a Z-form.
[0033] In this specification, unless otherwise specified, the
concentration of air in a gas phase of the hydrochlorofluoroolefin
is the concentration of air at a gas temperature of 25.degree. C.
In this specification, air comprises 20 vol % of oxygen and 80 vol
% of nitrogen to the total volume of air.
[0034] According to a first embodiment of the present invention,
provided is a method for storing a hydrochlorofluoroolefin in a
sealed storage container, wherein the hydrochlorofluoroolefin is
stored in such a state that a gas phase and a liquid phase coexist
in the storage container, and the concentration of air in the gas
phase in the storage container at a temperature of 25.degree. C. is
kept to be at most 3.0 vol %. In the sealed container, the
hydrochlorofluoroolefin is kept in a gas-liquid coexistence state,
and therefore, the pressure of the hydrochlorofluoroolefin in the
storage container is a saturated vapor pressure of the
hydrochlorofluoroolefin. The concentration of air may be regarded
as a proportion of air contained in the gas phase in the storage
container containing the hydrochlorofluoroolefin and air.
[0035] A part of the hydrochlorofluoroolefin in a storage container
is taken out, and thereafter, the rest of the
hydrochlorofluoroolefin will be continuously stored in the storage
container in not a few cases. In such a case, the volume of the gas
phase in the storage container increases, but the concentration of
air in the gas phase having the volume increased will be kept to be
at most 3.0 vol %. The concentration of air in the gas phase is
usually in an equilibrium state with the concentration of air in
the hydrochlorofluoroolefin in the liquid phase, and therefore, it
is considered that unless air enters into the storage container
when the part of the hydrochlorofluoroolefin is taken out, the
concentration of air in the gas phase would not substantially
increase.
[0036] According to a second embodiment of the present invention,
provided is a storage container for a hydrochlorofluoroolefin,
which is a sealed storage container in which the
hydrochlorofluoroolefin is filled in such a state that a gas phase
and a liquid phase coexist, and in which the concentration of air
in the gas phase at a temperature of 25.degree. C. is at most 3.0
vol %.
[0037] According to a third embodiment of the present invention,
provided is a method for storing a hydrochlorofluoroolefin in a
sealed storage container, wherein the hydrochlorofluoroolefin is
stored in such a state that a gas phase and a liquid phase coexist
in the storage container, and the concentration of oxygen in the
gas phase in the storage container at a temperature of 25.degree.
C. is kept to be at most 0.6 vol %.
[0038] According to a fourth embodiment of the present invention,
provided is a storage container for a hydrochlorofluoroolefin,
which is a sealed storage container in which the
hydrochlorofluoroolefin is filled in such a state that a gas phase
and a liquid phase coexist, and in which the concentration of
oxygen in the gas phase at a temperature of 25.degree. C. is at
most 0.6 vol %.
[0039] In the first to fourth embodiments of the present invention,
as the hydrochlorofluoroolefin, specifically, a 02-10
hydrochlorofluoroolefin may be mentioned. The
hydrochlorofluoroolefin to which the present invention is suitably
applicable, has from 2 to 8 carbon atoms, more preferably from 2 to
5 carbon atoms.
[0040] The C.sub.2 hydrochlorofluoroolefin may be
1-chloro-2,2-difluoroethylene (HCFO-1122),
1,2-dichlorofluoroethylene (HCFO-1121) or 1-chloro-2-fluoroethylene
(HCFO-1131).
[0041] The C.sub.3 hydrochlorofluoroolefin may, for example, be
1-chloro-2,3,3,3-tetrafluoropropene (HCFO-1224yd),
2-chloro-1,3,3,3-tetrafluoropropene (HCFO-1224xe),
1-chloro-1,3,3,3-tetrafluoropropene (HCFO-1224zb),
2-chloro-3,3,3-trifluoropropene (HCFO-1233xf),
1-chloro-2,3,3-trifluoropropene (HCFO-1233yd),
1-chloro-3,3,3-trifluoropropene (HCFO-1233zd),
1-chloro-1,3,3-trifluoropropene (HCFO-1233zb),
2-chloro-1,3,3-trifluoropropene (HCFO-1233xe),
2-chloro-1,1,3-trifluoropropene (HCFO-1233xc),
3-chloro-1,2,3-trifluoropropene (HCFO-1233ye),
3-chloro-1,1,2-trifluoropropene (HCFO-1233yc),
1,2-dichloro-3,3,3-trifluoropropene (HCFO-1223xd),
1,3-dichloro-2,3,3-trifluoropropene (HCFO-1223yd),
2,3-dichloro-3,3-difluoropropene (HCFO-1232xf),
1,2,3-trichloro-3,3-difluoropropene (HCFO-1222xd) or
2,3,3-trichloro-3-fluoropropene (HCFO-1231xf).
[0042] The C.sub.5 hydrochlorofluoroolefin may, for example, be
1-chloro-2,3,3,4,4,5,5-heptafluoro-1-pentene (HCFO-1437dycc).
[0043] In the first to fourth embodiments of the present invention,
the hydrochlorofluoroolefin may be stored as a mixture of a plural
types of hydrochlorofluoroolefins, or may be stored alone.
[0044] The storage container for a hydrochlorofluoroolefin does not
require any special structure or material, so long as it is a
sealed container capable of enclosing a gas-liquid mixture under
internal pressure, and it may have a wide range of forms and
functions. For example, a storage tank being a fixed storage
container, or a pressure resistant container such as a filling
cylinder or a secondary filling cylinder (service can) to be used
for transportation, may be mentioned. As the material for the
storage container, it is possible to use, for example, a metal
composed mainly of one material or two or more materials selected
from carbon steel, manganese steel, chromium-molybdenum steel,
other low alloy steel, stainless steel, aluminum alloy, copper,
iron, aluminum, nickel, titanium, metal silicon, silicon steel,
tin, magnesium and a zinc.
[0045] According to the first and second embodiments of the present
invention, the concentration of air in the gas phase in the storage
container is at most 3.0 vol %. When the concentration of air in
the gas phase is at most 3.0 vol %, decomposition, oxidation or the
like of the hydrochlorofluoroolefin in a liquid phase and in a gas
phase can be sufficiently prevented, and the quality can be
maintained.
[0046] According to the third and fourth embodiments of the present
invention, the concentration of oxygen in the gas phase in the
storage container is at most 0.6 vol %. When the concentration of
oxygen in the gas phase is at most 0.6 vol %, decomposition,
oxidation or the like of the hydrochlorofluoroolefin in a liquid
phase and in a gas phase can be sufficiently prevented, and the
quality can be maintained.
[0047] The present inventors have found that a hydrofluoroolefin
having an unsaturated double bond like the hydrochlorofluoroolefin
undergoes a polymerization reaction in the presence of a small
amount of oxygen, whereas the hydrochlorofluoroolefin does not
undergo a polymerization reaction even in the presence of oxygen to
such an extent that a hydrofluoroolefin undergoes a polymerization
reaction.
[0048] And, the present inventors have conducted extensive studies
on the basis of discoveries such that for storage of the
hydrochlorofluoroolefin, the amount of presence of oxygen or air
containing oxygen can be defined from the viewpoint different from
that of the hydrofluoroolefin, and as a result, found that the
quality of the hydrochlorofluoroolefin can be maintained when the
concentration of air in the gas phase is at most 3.0 vol %, or the
concentration of oxygen is at most 0.60 vol %. To maintain higher
quality of the hydrochlorofluoroolefin in a longer period of time,
it is preferred that the concentration of air in the gas phase is
at most 1.7 vol % and the concentration of oxygen is at most 0.34
vol %, and it is more preferred that the concentration of air is at
most 0.7 vol % and the concentration of oxygen is at most 0.14 vol
%.
[0049] As described above, in the first and second embodiments of
the present invention, to define the concentration of air in the
gas phase to be at most a specific value is synonymous with
defining the concentration of oxygen to be at most one fifth of the
specific value of the air concentration. In the present invention,
when the hydrochlorofluoroolefin is stored in a storage container,
usually, the amount of air or oxygen included in the storage
container is defined as above, whereby the amount of oxygen which
accelerates decomposition, oxidation or the like of the
hydrochlorofluoroolefin is defined.
[0050] From the viewpoint of operation property at the time of
filling in a storage container, the concentration of air in the gas
phase is preferably from 1.8 to 3.0 vol %, and the concentration of
oxygen is preferably from 0.36 to 0.6 vol %.
[0051] Further, the concentration of air in the gas phase is at
least 1 vol ppm, whereby the production cost, etc. can be
suppressed. In view of the production cost, the concentration of
air in the gas phase is more preferably at least 3 vol ppm, further
preferably at least 5 vol ppm, particularly preferably at least 7
vol ppm. The concentration of oxygen in the gas phase is preferably
at least 0.2 vol ppm, whereby the production cost, etc. can be
suppressed. In view of the production cost, the concentration of
air in the gas phase is more preferably at least 0.6 vol ppm,
further preferably at least 1 vol ppm, particularly preferably at
least 1.4 vol ppm.
[0052] In the first and second embodiments of the present
invention, the concentration of air in the gas phase is, from the
above-described viewpoint, preferably at least 1 vol ppm and at
most 3.0 vol %, more preferably at least 3 vol ppm and at most 1.7
vol %, further preferably at least 3 vol ppm and at most 0.7 vol
%.
[0053] In the third and fourth embodiments of the present
invention, the concentration of oxygen in the gas phase is, from
the above-described viewpoint, preferably at least 0.2 vol ppm and
at most 0.6 vol %, more preferably at least 0.6 vol ppm and at most
0.34 vol %, further preferably at least 0.6 vol ppm and at most
0.14 vol %.
[0054] The hydrochlorofluoroolefin to which the first to fourth
embodiments of the present invention are more suitably applicable,
among the above hydrochlorofluoroolefins, may be the C.sub.3
hydrochlorofluoropropene, preferably at least one member selected
from a monochlorotetrafluoropropene and a
monochlorotrifluoropropene, particularly preferably HCFO-1224yd
(hereinafter sometimes referred to as "1224yd").
[0055] 1224yd (CF.sub.3--CF.dbd.CHCl) has high stability among
hydrochlorofluoroolefins. Therefore, when the first and second
embodiments of the present invention are applied to 1224yd, the
lower limit of the concentration of air in the gas phase may be
set, for example, at 10 vol ppm, more preferably 15 vol ppm. When
the third and fourth embodiments of the present invention are
applied to 1224yd, the lower limit of the concentration of oxygen
in the gas phase may be set, for example, at 2 vol ppm, more
preferably 3 vol ppm.
[0056] 1224yd has cis-trans isomers 1224yd(Z) and 1224yd(E), and
1224yd(Z) has high chemical stability as compared with 1224yd(E).
1224yd has, from the viewpoint of chemical stability, a proportion
of 1224yd(Z) to the total amount of 1224yd of preferably from 30 to
100 mass %, more preferably from 50 to 100 mass %, further
preferably from 80 to 100 mass %, particularly preferably from 99
to 100 mass %. 1224yd particularly preferably consists solely of
1224yd(Z). When the first and second embodiments of the present
invention are applied to 1224yd(Z), the lower limit of the
concentration of air in the gas phase may be set, for example, at
20 vol ppm, more preferably 25 vol ppm, further preferably 50 vol
ppm, most preferably 80 vol ppm.
[0057] When the third and fourth embodiments of the present
invention are applied to 1224yd(Z), the lower limit of the
concentration of oxygen in the gas phase may be set, for example,
at 4 vol ppm, more preferably 5 vol ppm, further preferably 10 vol
ppm, most preferably 16 vol ppm.
[0058] In the first to fourth embodiments of the present invention,
in the storage container, in addition to the
hydrochlorofluoroolefin and air or oxygen, trace components may be
present within a range not to impair the effects of the present
invention. The trace components may be by-products formed in
production of the hydrochlorofluoroolefin, unreacted raw materials,
and various compounds used for purification. In such a case, the
concentration of air or oxygen in the gas phase is the
concentration of air or oxygen to a gas phase portion in the
storage container in which the hydrochlorofluoroolefin, the trace
components and air are contained.
[0059] The content of such trace components is, for example, to the
total amount of the hydrochlorofluoroolefin to be stored and the
trace components, preferably less than 1.5 mass % in total, more
preferably at most 1.0 mass %. However, in the first to fourth
embodiments of the present invention, from the viewpoint of the
production cost, the lower limit of the content of the trace
components may be preferably 4 mass ppm, more preferably 50 mass
ppm, further preferably 100 mass ppm. So long as the content of the
trace components is at most the upper limit value, even if it is at
least the above lower limit value, in the first to fourth
embodiments of the present invention, the concentration of air or
oxygen in the gas phase is sufficiently suppressed, and therefore
the effects of the present invention can be achieved.
[0060] In the first to fourth embodiments of the present invention,
in a case where 1224yd is stored in the storage container, such
trace components may be at least one member selected from
1,3-dichloro-1,1,2,2,3-pentafluoropropane
(CClF.sub.2--CF.sub.2--CHClF, HCFC-225cb),
1,1,1,2-tetrafluoropropane (CF.sub.3--CHF--CH.sub.3, HFC-254eb),
1,1-dichloro-2,3,3,3-tetrafluoropropene
(CF.sub.3--CF.dbd.CCl.sub.2, CFO-1214ya),
(Z)-2-chloro-1,3,3,3-tetrafluoropropene ((Z)-CF.sub.3--CCl.dbd.CHF,
HCFO-1224xe(Z)), (E)-2-chloro-1,3,3,3-tetrafluoropropene
((E)-CF.sub.3--CCl.dbd.CHF, HCFO-1224xe(E)),
2,3,3,3-tetrafluoropropene (CF.sub.3--CF.dbd.CH.sub.2, HFO-1234yf),
(Z)-1,3,3,3-tetrafluoropropene ((Z)--CF.sub.3--CH.dbd.CHF,
HFO-1234ze(Z)), (E)-1,3,3,3-tetrafluoropropene
((E)-CF.sub.3--CH.dbd.CHF, HFO-1234ze(E)),
1-chloro-3,3,3-trifluoro-1-propyne (CF.sub.3--C.ident.CCl),
fluorinated hydrocarbon represented by C.sub.4H.sub.4F.sub.4,
2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb),
1,1,1,3,3-pentafluoropropane (HFC-245fa),
2-chloro-1,1,3,3,3-pentafluoro-1-propene (CFO-1215xc),
3,3-dichloro-1,1,1,2,2-pentafluoropropane (HCFC-225ca),
1,1,1,2,2,3,3-heptafluoropropane (FC-227ca), methanol, ethanol,
acetone, chloroform and hexane.
[0061] Further, the above trace components may sometimes have,
depending upon the type of the compound, a specific function when
contained in an appropriate amount of less than 1.5 mass % to the
total amount of 1224yd and the trace components. For example,
1-chloro-3,3,3-trifluoro-1-propyne is a compound which increases
stability of 1224yd when contained in an amount of less than 1.5
mass % to the total amount of 1224yd and the trace components. From
the viewpoint of stability of 1224yd,
1-chloro-3,3,3-trifluoro-1-propyne is contained in an amount of
from 0.0001 to 0.1 mass %, more preferably from 0.0001 to 0.001
mass % to the total amount of 1224yd and the trace components.
[0062] Further, for example, HCFC-244bb is a compound which
increases stability of 1224yd when contained in an amount of less
than 1.5 mass % to the total amount of 1224yd and the trace
components. From the viewpoint of stability of 1224yd, HCFC-244bb
is contained preferably in an amount of from 0.001 to 0.5 mass %,
more preferably from 0.01 to 0.1 mass % to the total amount of
1224yd and the trace components.
[0063] Further, the trace components may contain a
hydrofluoroolefin, for example, in the case of 1224yd, HF-1234yf,
HFO-1234ze(E), HFO-1234ze(Z) and fluorinated hydrocarbon
represented by C.sub.4H.sub.4F.sub.4. However, the
hydrofluoroolefin may be polymerized in the presence of a very
small amount of oxygen to form a solid polymerized product in the
container, and accordingly the content of the hydrofluoroolefin to
the total amount of the hydrochlorofluoroolefin to be stored and
the trace components is preferably at most 5,000 mass ppm in total,
more preferably at most 2,000 mass ppm. Considering the production
cost, the lower limit of the content of the hydrofluoroolefin to
the total amount of the hydrochlorofluoroolefin to be stored and
the trace components is preferably 50 mass ppm, more preferably 100
mass ppm.
[0064] In a case where 1224yd is stored in the storage container,
if the above trace components are present, it is preferred that the
amount of air in the storage container is from 5 vol ppm to 1.5 vol
%, or the amount of oxygen is from 1 vol ppm to 0.3 vol %, with a
view to further improving the stability of 1224yd, and it is more
preferred that the amount of air is from 7 vol ppm to 1.0 vol %, or
the amount of oxygen is from 1.4 vol ppm to 0.2 vol %.
[0065] Further, according to the first to fourth embodiments of the
present invention, it is preferred that no water is contained in
the storage container. The upper limit of the amount of water which
can be contained without impairing the effects of the present
invention is preferably 20 mass ppm, more preferably 15 mass ppm,
further preferably 10 mass ppm, particularly preferably 5 mass ppm
to the total amount of the desired hydrochlorofluoroolefin and the
trace components. Considering the production cost, the lower limit
of the amount of water is preferably 0.1 mass ppm, more preferably
1 mass ppm, to the total amount of the hydrochlorofluoroolefin to
be stored and the trace components.
[0066] In order that the amount of water in the storage container
is within the above range, before the hydrochlorofluoroolefin is
filled in the storage container, the amount of water in the
hydrochlorofluoroolefin can be reduced by a known method such as
bringing the hydrochlorofluoroolefin into contact with a solid
adsorbent such as molecular sieves. The amount of water in the
hydrochlorofluoroolefin may be measured by Karl Fischer coulometric
titration method.
[0067] In the first to fourth embodiments of the present invention,
adjustment of the concentration of air or oxygen in the gas phase
may be conducted by pressurizing the hydrochlorofluoroolefin to
form a liquid and injecting this liquid into a sealed container
having the concentration of air reduced to at most 3.0 vol % at a
temperature of 25.degree. C. or the concentration of oxygen reduced
to at most 0.6 vol % at a temperature of 25.degree. C. by
preliminary vacuum deaeration of air. When the liquid of the
hydrochlorofluoroolefin is injected into the container, the space
in the container will be quickly saturated with the vapor from the
liquid. And, in the gas phase gas filled with saturated vapor of
the hydrochlorofluoroolefin, the concentration of air becomes to be
at most 3.0 vol % (temperature: 25.degree. C.) or the concentration
of oxygen becomes to be at most 0.6 vol % (temperature: 25.degree.
C.). The concentrations of air and oxygen in the gas phase may be
measured by gas chromatography.
[0068] In the first to fourth embodiments of the present invention,
the acid content of the hydrochlorofluoroolefin in the storage
container after left to stand in a constant temperature state of
125.degree. C. for 5 days is preferably less than 30 mass ppm, more
preferably less than 10 mass ppm, further preferably less than 1
mass ppm to the total amount of the hydrochlorofluoroolefin. The
acid content in the storage container is obtained by the
measurement method disclosed in the after-described Examples. In a
case where the trace components are present in the storage
container, the acid content to the total amount of the
hydrochlorofluoroolefin and the trace components is preferably less
than 30 mass ppm.
[0069] According to such a storage method for the
hydrochlorofluoroolefin of the present invention, the
hydrochlorofluoroolefin filled in a gas-liquid state in the sealed
container will not undergo decomposition, oxidation or the like,
whereby it is possible to maintain the purity and the high quality
as a refrigerant or the like, of the hydrochlorofluoroolefin.
Further, in a preferred embodiment such that the lower limit of the
concentration of air in the gas phase is 1 vol ppm or the lower
limit of the concentration of oxygen is 0.2 vol ppm, the
hydrochlorofluoroolefin can be stored at a low cost. Further, by
defining the content of the hydrofluoroolefin as the trace
components, no solid polymerized product will be formed in the
sealed container, whereby clogging of a valve, etc. or
contamination to the refrigerating system, is less likely to
occur.
[0070] Evaluation of the storage method of the present invention
may be conducted, for example, in such a manner that the
hydrochlorofluoroolefin is injected together with a predetermined
amount of air or oxygen into a sealed container to achieve a
gas-liquid coexistence state, and the entirety is heated to a
predetermined temperature and held in a constant temperature state
for a predetermined time, whereupon reaction products in the liquid
phase of the hydrochlorofluoroolefin will be identified and
analyzed. This evaluation corresponds to an accelerated test in
which a thermal load is applied. The heating temperature may be set
in a range of from -70 to 300.degree. C. which is a set temperature
range of the constant temperature vessel. Further, the heat
treatment time may be optionally set. The identification and
analysis of the reaction products may be carried out, for example,
by the methods described in Examples given hereinafter.
EXAMPLES
[0071] Now, the present invention will be described in detail with
reference to Examples, but the present invention is by no means
limited to the following Examples. Ex. 1 to 8 are Examples of the
present invention, and Ex. 9 and 10 are Comparative Examples. Ex.
11 to 13 are Reference Examples using a hydrofluoroolefin.
Ex. 1 to 10
[0072] In a SUS316 pressure-resistant container having an internal
volume of 200 cc (maximum operating temperature: 300.degree. C.,
maximum working pressure: 20 MPa), a tube made of Pyrex (registered
trademark) having the weight preliminarily measured, was inserted.
The pressure-resistant container was sealed, and the container was
evacuated of air. The tube was inserted to confirm the presence or
absence of formation of a polymer in the pressure-resistant test
container. Then, a predetermined amount of air was introduced into
the pressure-resistant container, and 50 g of a 1224yd(Z)
composition containing liquified 1224yd(Z) and trace components was
filled. The gas phase in the pressure-resistant container was
collected, and the concentration of air was measured by gas
chromatography, whereupon a value shown in Table 1 was obtained.
The temperature in the pressure-resistant container when the sample
was collected was 25.degree. C. The concentration of oxygen
determined from the concentration of air is shown in Table 1.
[0073] The trace components in the 1224yd(Z) composition were
HFC-254eb, HFO-1234ze(Z), fluorinated hydrocarbon represented by
C.sub.4H.sub.4F.sub.4, HCFC-244bb, HFC-245fa, CFO-1215xc, FC-227ca,
HCFO-1224xe, HFO-1224yd(E), 1-chloro-3,3,3-trifluoro-1-propyne,
HFO-1234yf and methanol, and their total content was 0.52 mass % to
the total amount of 1224yd(Z) and the trace components. Further,
the content of water was 20 mass ppm to the total amount of
1224yd(Z) and the trace components.
[0074] Then, the pressure-resistant container in which the
1224yd(Z) composition together with air at a predetermined
concentration was filled, was placed in a hot air circulating
constant temperature vessel and left to stand in a constant
temperature state of 125.degree. C. for 5 days.
[0075] Upon expiration of the 5 days, the pressure-resistant
container was taken out from the constant temperature vessel, and
the acid content in the 1224yd(Z) composition was analyzed as
follows.
[0076] (Measurement of Acid Content)
[0077] The pressure-resistant container after the above test was
left at rest until the temperature reached room temperature. To the
pressure-resistant container at room temperature, a set of four
absorption bottles each having 100 ml of pure water put, connected
by a conductor tube in series, was connected, and the valve of the
pressure-resistant container was gradually opened to introduce the
1224yd(Z) composition into water in the absorption bottles so that
the acid content contained in the 1224yd(Z) composition was
extracted.
[0078] The water in the first and second absorption bottles after
extraction was titrated by a 1/100N-NaOH alkali standard solution
with a drop of an indicator (BTB: bromothymol blue). Further, the
water in the third and fourth absorption bottles were similarly
titrated as a measurement blank. From such measured value and the
measurement blank value, the concentration of the acid content
contained in the 1224yd(Z) composition after the test was obtained
as the HCl concentration. The results are shown in Table 1. In
Table 1, .circleincircle. represents an acid content concentration
of less than 1 mass ppm, .largecircle. an acid content
concentration of at least 1 mass ppm and less than 10 mass ppm,
.DELTA. an acid content concentration of at least 10 mass ppm and
less than 30 mass ppm, and x an acid content concentration of at
least 30 mass ppm.
[0079] Further, while the presence or absence of formation of a
solid substance in the tube was visually examined, and the amount
of the solid substance formed was examined by a mass change of the
tube between before and after the test. The results are shown in
Table 1. In Table 1, .largecircle. represents an amount of the
solid substance formed of at most 10 mg, and x an amount of the
solid substance formed of more than 10 mg.
Ex. 11 to 13
[0080] For comparison with the hydrochlorofluoroolefin (HCFO), the
following three types of hydrofluoroolefins (HFO) were filled in a
pressure-resistant container so that the air concentration and the
oxygen concentration in the gas phase were the same as in Ex. 3,
and the same evaluations as above were conducted. The results are
shown in Table 1.
[0081] HFO-1234yf having a purity of at least 99.5 mass % was used
in Ex. 11, HFO-1234ze(E) having a purity of at least 99.5 mass % in
Ex. 12, and trifluoroethylene (HFO-1123) having a purity of at
least 99.5 mass % in Ex. 13.
TABLE-US-00001 TABLE 1 Concentration in Acid content Amount of
solid gas phase (vol %) concentration substance formed Ex. Type
Sample Air Oxygen Evaluation Evaluation Ex. 1 HCFO 1224yd(Z) 0.01
0.002 .circleincircle. .largecircle. Ex. 2 composition 0.1 0.02
.circleincircle. .largecircle. Ex. 3 0.3 0.06 .circleincircle.
.largecircle. Ex. 4 0.8 0.2 .largecircle. .largecircle. Ex. 5 1.3
0.26 .largecircle. .largecircle. Ex. 6 1.8 0.36 .DELTA.
.largecircle. Ex. 7 2.1 0.42 .DELTA. .largecircle. Ex. 8 2.5 0.50
.DELTA. .largecircle. Ex. 9 3.1 0.62 X .largecircle. Ex. 10 4 0.8 X
.largecircle. Ex. 11 HFO 1234yf 0.3 0.06 X X Ex. 12 1234ze(E) 0.3
0.06 X X Ex. 13 1123 0.3 0.06 X X
[0082] It is found from Table 1 that the method of the present
invention is effective as a stable storage method to store a
hydrochlorofluoroolefin, which does not bring about decomposition
and oxidation over a long period of time.
INDUSTRIAL APPLICABILITY
[0083] According to the storage method and the storage container of
the present invention, the hydrochlorofluoroolefin does not undergo
decomposition, oxidation or the like, whereby they can be useful
for storage, transportation, etc. while high quality of the
hydrochlorofluoroolefin is maintained.
* * * * *